Add the AzureFunctions feeds as a NuGet package sources (#934)

* Remove feeds from myget.org

* Add AzureFunctions@internalrelease feed

* Add AzureFunctions@staging feed

Author: Francisco-Gamino

NuGet.config

@@ -2,9 +2,7 @@
 <configuration>
   <packageSources>
     <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
-    <add key="azure_app_service" value="https://www.myget.org/F/azure-appservice/api/v2" />
-    <add key="azure_app_service_staging" value="https://www.myget.org/F/azure-appservice-staging/api/v2" />
-    <add key="buildTools" value="https://www.myget.org/F/30de4ee06dd54956a82013fa17a3accb/" />
-    <add key="AspNetVNext" value="https://www.myget.org/F/aspnetcore-dev/api/v3/index.json" />
+    <add key="AzureFunctions@internalrelease" value="https://azfunc.pkgs.visualstudio.com/e6a70c92-4128-439f-8012-382fe78d6396/_packaging/AzureFunctions%40internalrelease/nuget/v3/index.json" />
+    <add key="AzureFunctions@staging" value="https://azfunc.pkgs.visualstudio.com/e6a70c92-4128-439f-8012-382fe78d6396/_packaging/AzureFunctions%40staging/nuget/v3/index.json" />
   </packageSources>
 </configuration>